Christoph Stefan Aigner

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OBJECTIVES In the brain and heart, oscillations at about 0.1Hz are conspicuous. It is therefore worthwhile to study the interaction between intrinsic BOLD oscillations (0.1Hz) and slow oscillations in heart rate interval (RRI) signals and differentiate between their neural and vascular origin. METHODS We studied the phase-coupling with a 3T scanner with(More)
RF pulse design via optimal control is typically based on gradient and quasi-Newton approaches and therefore suffers from slow convergence. We present a flexible and highly efficient method that uses exact second-order information within a globally convergent trust-region CG-Newton method to yield an improved convergence rate. The approach is applied to the(More)
 Radio frequency (RF) pulses are essential in MRI to excite and alter magnetization. We present and validate a flexible approach based on optimal control of the full time-dependent Bloch equation, including relaxation effects. A globally convergent trust-region Newton method with exact derivatives via adjoint calculus allows the efficient computation of(More)
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